The present invention relates to a liquid crystal display having an improved impact resistance and being restrained from being curved or deformed.
In recent years, a display for information-communication equipment is improved significantly. Particularly, a liquid crystal display can be decreased in its thickness and weight in comparison with a braun tube and improved in technique for increasing view angle and moving image, so that the liquid crystal display is necessary for mobile equipment or consumer digital electronics. It is desired for the liquid crystal display to have a size increased in accordance with a market requirement.
A substrate of the liquid crystal display is generally a glass plate having a thickness not more than 1 mm. An impact resistance of the glass plate decreases in accordance with an increase in area of its surface. Therefore, in the prior art, the impact resistance decreases significantly in accordance with increase of the size thereof. Incidentally, there is a provability of that the impact insufficient for destroying the glass plate as a pressure from an outside of the display generates a local shift or gap between the glass plates between which a liquid crystal layer is arranged, to cause a deterioration of displayed image.
Further, a thermal energy generated by a light source increases in accordance with an increase in quality and brightness of the image. When the light source is excited, a temperature of a side of the panel facing to the light source is increased to increase a difference in temperature between the side of the panel facing to the light source and another side thereof facing to a viewer. Therefore, the panel is curved or deformed. Particularly, the panel including a plate for generating a difference in phase is curved significantly. Such deformation of the panel causes an irregularity in the image.
Further, an increase of a time period during which the light source is continuously excited causes a deformation (expansion or contraction) of a polarizing plate so that the glass plate adjacent to the polarizing plate is deformed or curved to deteriorate the quality of the displayed image. Further, a stress concentration is generated at a boundary between the polarizing plate and the glass plate by the deformation of the polarizing plate to cause a removal or clearance at the boundary.
JP-A-2004-181975 and JP-A-2005-134841 disclose a shock absorbing layer arranged on the another side of the glass substrate facing to the viewer to improve the impact resistance. JP-A-2003-84270 discloses an adhesive as the shock absorbing layer between the substrate and the polarizing plate. By such arrangements, the shift between the polarizing plate and the substrate and the disturbance in orientation of the liquid crystal is restrained from being generated by the stress applied from the outside. JP-A-8-110521 discloses a liquid crystal panel including a liquid crystal cell, the polarizing plates between which the liquid crystal cell is arranged, and resin plates adhered to respective outer sides of the polarizing plates and having a contraction rate smaller than that of the polarizing plates and an elastic modulus higher than that of the polarizing plates. By this arrangement, the polarizing plates are restrained by a rigidity of the resin plates from being contracted when receiving a high temperature.